Scum removal apparatus

ABSTRACT

A scum removal apparatus operable in association with a movable member operating within a sewage treatment pool is provided with a trough, a weir member and a transmission mechanism. The trough is fixed in position, and the transmission mechanism transmits a force from the movable member to the weir member to cause the latter to move up and down with respect to a fluid surface level. When the weir member is sunken, the scum is drawn into the trough, while when the weir member floats above the fluid surface level, the drawing of the scum into the trough is interrupted. 
     Support of the weir member is carried out through a rotary shaft and the weir member is employed in the form of an elongated member having an elliptical cross-section so that the drawing of the scum can be carried out smoothly and stably with the transmission mechanism simplified in structure. 
     Sealing between the weir member and the trough is assuredly and simply achieved by a fixed-type sealing means on the side of the trough and end plates of the weir member.

FIELD OF THE INVENTION

The present invention generally relates to a scum removal apparatus forefficiently removing scum floating in a sewage treatment pool and, moreparticularly, to the simplified scum removal apparatus of a typeeffective to efficiently remove scum by the utilization of a drivingpower generated by a movable member installed in the sewage treatmentpool and without relying on a dedicated driving power.

BACKGROUND ART

FIGS. 25 and 26 of the accompanying drawings illustrate the scum removalapparatus suggested by the inventor of the present invention. Agenerally rectangular sewage settling pool is provided with a pluralityof, for example, four, sprocket shafts 200 extending in a widthwisedirection of the sewage settling pool, a pair of sprocket wheels 201mounted on each of the sprocket shafts 200 and generally endless,left-hand and right-hand chains trained around the sprocket wheels 201on the sprocket shafts 200. In the suggested scum removal apparatus,some or all of the flights 203 secured to the chains 202 are driventogether with the chains 202 to draw and remove the scum floating on thewater surface in the sewage settling pool.

The scum removal apparatus includes a trough 205, a guide support sheet206, a weir member 208 and a transmission mechanism 209. The trough 205is in the form of an elongated member of a generally U-shapedcross-section opening upwardly and frontwardly and is fixedly disposedin the sewage settling pool so as to extend in the widthwise directionof the sewage settling pool.

The guide support sheet 206 is a band of rubber material of a lengthcorresponding to that of the trough 205 and secured at one front sideportion to an upper edge of a front wall of the trough 205 with theopposite rear side portion thereof protruding frontwardly from the frontwall of the trough 205 so as to undergo undulation by the effect of itselastic deformation.

The weir member 208 is in the form of a generally elongated memberhaving a front portion of a generally fight triangular hollowcross-section and a rear portion of a generally rectangularcross-section and has a base portion secured to the front side portionof the guide support sheet 206 so as to protrude outwardly therefrom sothat, while supported by the guide support sheet 208, the weir member206 can undergo a wavy motion above and below the fluid surface level207 of sewage in the sewage settling pool.

It is the transmission mechanism 209 that drive the weir member 208 tomove up and down with respect t the fluid surface level 207 in thesewage settling pool. This transmission mechanism 209 includes a rotarysupport shaft 210, a drive arm 211, and an operating arm 212. The rotarysupport shaft 210 is supported so as to extend widthwise of the sewagesettling pool whereas the drive arm 211 is supported so as to extendfrom one end portion of the rotary support shaft 210 in a frontwarddirection substantially perpendicular to the rotary support shaft 210.The operating arm 212 is supported so as to extend in a directioncounter to the direction of extension of the drive arm 211 and towardsthe trough 205 and is employed for each of the left-hand and right-handsides of the sewage settling pool for the purpose of a stabilizedoperation. The drive arm 211 has a front end portion provided with afollow-up member 213.

The follow-up member 213 has a cam face defined at a bottom thereof,which cam face is constituted by two hill areas 213a and 213c and a dalearea 213b positioned between these hill areas 213a and 213c. It is aroller (a drive unit) 214, protruding outwardly from one end of eachflight (mud dragging member) 203, that drives the follow-up member 213to actuate the drive arm 211 and the operating arm 212 to move the weirmember 208 up and down with respect to the fluid surface level 207 ofsewage in the sewage settling pool. This roller 214 is supported by abracket secured to one end of the follow-up member 213 associated witheach flight 203. Reference numeral 220 shown in FIGS. 25 and 26represents a side seal (a sealing means) disposed between each side endof the weir member 208 and the adjacent side end of the trough 205 foravoiding a leakage of scum and water. This side seal is made of rubbermaterial and is corrugated into a bellows between each side end of theweir member 203 and the adjacent side end of the trough 205 so that itcan selectively expand and contract due to its elasticity in response toan undulating motion of both of the weir member 208 and the guidesupport sheet 206.

The suggested scum apparatus shown in FIGS. 25 and 26 operates in thefollowing manner.

When a drive motor (not shown) installed on a ground outside the sewagesettling pool is powered, the chains 202 are driven so that the flights203 coupled with the chains 202 are driven so as to slowly circulatealong a generally rectangular path as indicated by the arrows in FIGS.25 and 26. The flights 203 being circulated successively scrape thesediment at the bottom of the sewage settling pool to guide it to a pit221 in the bottom of the sewage settling pool so that the sediment soguided into the pit 221 can be subsequently discharged by a suitablepump (not shown) to the outside of the sewage settling pool.

Some of the flights 203 moving along a path adjacent the fluid surfacelevel 207 during the circulatory motion thereof successively push thefollow-up members 213 by means of the rollers 214. The rollers 214 arethen brought into engagement with the follow-up members 213 in a firststage, first contacting the hill area 213a, then contacting the dalearea 213b and finally contacting the hill area 213c, to thereby move thefollow-up members 213 up and down. When each roller 214 is brought intoengagement with the hill area 213a of the respective follow-up member213, both of the follow-up member 213 and the associated drive arm 211are lifted a considerable distance and, at the same time, the associatedoperating arm 212 is lowered, causing the weir member 208 to be pushedbeneath the fluid surface level 207 by means of a rod 224.

At this time, the scum S floating on the top surface of the sewage,regardless of the size thereof, are guided into the trough 205 by theflow of water and is then discharged out from the trough 205. When eachroller 214 is however brought into engagement with the dale area 213a ofthe respective follow-up member 213 in a second stage, both of thefollow-up member 213 and the drive arm 211 are temporarily lowered whilethe associated operating arm 212 is lifted. Consequently, the weirmember 208 having been lowered beneath the fluid surface level 207 iselevated a slight distance and, therefore, the amount of water componentflowing over the weir member 208 into the trough 25 becomes small.Although the amount of the water component flowing over the weir member208 is small, the velocity of flow of the water component becomes sohigh as to result in an increase of the force with which the scum S isdrawn towards the trough 205. Therefore, scum lumps, small and large insize and/or floating near and a substantial distance away from thetrough 205, can be smoothly drawn close towards the trough 205.

On the other hand, when each roller 214 is subsequently brought intoengagement with the hill area 213c of the respective follow-up member213 in a third stage, both of the follow-up member 213 and the drive arm211 are again elevated and the associated operating arm 212 is lowered.Once this occurs, the weir member 208 is lowered to guide a substantialamount of the scum S, drawn close towards the trough 205 in the mannerdescribed above, into the trough 205. Thus, since the follow-up member213 moves so as to perform the three stages, the draw of the scum S tothrow it into the trough 205 can be performed with considerably highefficiency.

However, the above described scum removal apparatus has been foundhaving the following problems.

Since the weir member 208 is supported by the guide support sheets 206made of rubber material, the weir member 208 is held in a instablecondition and, accordingly, the use of the plural operating arms 212 andalso the use of the rotary support shaft 210 having a lengthcorresponding to the width of the sewage settling pool are required,making the scum removal apparatus as a whole complicated in structureand costly to assembly. Also, since the operating performance of theweir member 208 is not consistent during the operation thereof, theamount of scum drawn thereby is not always constant.

Since the weir member 208 is in the form of a generally elongated memberhaving a front portion of a generally right triangular hollowcross-section and a rear portion of a generally rectangularcross-section and is of one-piece construction, the molding thereof isvery complicated and requires a high cost. Also, there is a problem inthat, since the top of the front portion of the weir member 208protrudes upwardly, some of the scum lumps tending to ride over thefront portion of the weir member 208 is often entangled, thereby failingto ride over the front portion of the weir member 208. Also, since therear portion of the weir member 208 is substantially in the form of arectangular-sectioned plate, some of the scum lumps having ridden overthe front portion of the weir member 208 tend to gather around the rearportion of the weir member 208 to such an extent that the weir member208 may fail to operate properly and that an outer appearance tends tobe spoiled.

Also, since the side seal 220 is in the form of bellows, not only doesit require a high cost, but the attachment thereof is also complicatedconsiderably.

Accordingly, the present invention has been devised to substantiallyeliminate the problems discussed above.

An object of the present invention is to make it possible tomanufacture, at a reduced cost, the scum removal apparatus as a wholewhich is simple in structure and wherein the weir member can operatestably even though the operating arm employed is a single short rotarysupport shaft and also to stabilize the operating performance of theweir member so that the amount of scum drawn can be maintained constant.

The molding of the weir member can be achieved simply and at a reducedcost, and can be so designed as to allow the scum to easily ride overthe weir member. Design has been made to avoid the scum from gatheringaround the weir member. Also, design has been made to avoid the scumfrom being accumulated on the way to thereby render the weir member tobe comfortable to look at.

Design has also been made to render the seal means to be simple instructure and inexpensive and to permit the attachment thereof to beperformed very simply.

DISCLOSURE OF THE INVENTION

The present invention is featured in that, in a scum removal apparatuswhich comprises a generally U-sectioned trough fixedly installed in asewage treatment pool, such as a sewage settling pool, with a lowerportion thereof submerged beneath a fluid surface level and with anupper portion thereof emerging upwardly above the fluid surface level,said trough having an opening defined at one side thereof, said troughbeing operable to discharging scum and a water component, which havebeen introduced thereinto through the opening; a weir member providedadjacent the opening of the trough so as to undergo a rocking motionwith an upper side portion thereof moving up and down with respect tothe fluid surface level for guiding and interrupting the flow of thescum and the water component into the trough; and a transmissionmechanism for transmitting a force to the weir member to cause the weirmember to undergo the rocking motion and including a follow-up memberadapted to be actuated in contact with a drive unit provided in each offlights within the treatment pool, one side of the trough adjacent theopening is provided with a rotary shaft extending parallel to the fluidsurface level to permit the weir member to move up and down, said weirmember being a generally elongated member having an ellipticalcross-section.

Also, in the above described scum removal apparatus, the presentinvention is featured in that one side of the trough adjacent theopening is provided with a rotary shaft extending parallel to the fluidsurface level to permit the weir member to move up and down, said weirmember being a generally elongated member having an ellipticalcross-section, and that said weir member has its opposite ends providedwith respective end plates while, on the side of the trough, sealingmeans are provided which are capable of permitting a movement in contactwith the end plates.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary perspective view of a scum removal apparatusaccording to a preferred embodiment of the present invention;

FIG. 2 is an exploded view of a sealing means used in the scum removalapparatus shown in FIG. 1;

FIG. 3 is a schematic side view of a portion of the scum removalapparatus shown in FIG. 1, showing a manner of removal of the scum;

FIG. 4 is an explanatory diagram showing an operating mode of the scumremoval apparatus shown in FIG. 1;

FIG. 5 is a fragmentary sectional view showing an another preferredembodiment of the present invention in which a supplemental element isfitted to a weir member;

FIG. 6 is a fragmentary perspective view showing one example of the scumremoval apparatus of a water-level follow-up type;

FIG. 7 is a schematic side sectional view of a portion of the scumremoval apparatus of the water-level follow-up type, showing a conditionbefore the scum is drawn;

FIG. 8 is a schematic side sectional view of the portion of the scumremoval apparatus of the water-level follow-up type, showing anothercondition during the drawing of the scum;

FIG. 9 is a fragmentary side sectional view showing another example ofthe scum removal apparatus of the water-level follow-up type;

FIG. 10 is a fragmentary side sectional view of the scum removalapparatus of the water-level follow-up type shown in FIG. 9, showing acondition during the drawing of the scum;

FIG. 11 is a fragmentary perspective view showing a novel exampleshowing a rigid connection of a trough with a connecting trough;

FIG. 12 is a sectional view, on an enlarged scale, showing an essentialportion of the example shown in FIG. 11;

FIG. 13 is a cross-sectional view taken along the line B--B in FIG. 12;

FIG. 14 is a cross-sectional view taken along the line C--C in FIG. 12;

FIG. 15 is a cross-sectional view taken along the line D--D in FIG. 12;

FIG. 16 is an exploded view showing another example of a method ofconnecting the connecting trough;

FIG. 17 is a schematic side view showing a vertically movable type ofthe weir member;

FIG. 18 is a schematic front elevational view showing an example inwhich the scum removal apparatus is operatively associated with a mudscraping device;

FIG. 19 is a partially sectioned perspective view showing an additionalexample of the weir member of a soft expandable type;

FIG. 20 is a longitudinal sectional view showing another drive mechanismfor the weir member;

FIG. 21 is a cross-sectional view taken along the line E--E in FIG. 20;

FIG. 22 is a sectional view, on an enlarged scale, of a portion of thedrive mechanism shown in FIG. 20;

FIG. 23 is a longitudinal sectional view showing a different drivemechanism for the weir member;

FIG. 24 is a longitudinal sectional view showing a further differentdrive mechanism for the weir member;

FIG. 25 is a fragmentary perspective view showing one example of theconventional scum removal apparatus; and

FIG. 26 is a schematic perspective view of the conventional scum removalapparatus shown in FIG. 25.

BEST MODE FOR CARRYING OUT THE INVENTION

To facilitate a better understanding of the present invention, thepresent invention will be described with reference to the accompanyingdrawings.

FIGS. 1 to 5 illustrate one embodiment of the present invention. In thisembodiment, there is shown a sewage settling pool (a treatment pool)rectangular in shape as viewed from above, and this rectangular sewagesettling pool is provided, as shown in FIG. 3, with a plurality of, forexample, four, sprocket shafts 300 supported so as to extend in awidthwise direction of the sewage settling pool, a pair of sprocketwheels 301 rigidly mounted on each of the sprocket shafts 300 andgenerally endless left-hand and right-hand chains 302 trained around therespective sprocket wheels 301 on each sprocket shaft 300. A pluralityof flights 303 are mounted on the endless chains 302 in a substantiallyequally spaced relationship around the chains 302 so that the flights303 can undergo a circulatory motion along a generally rectangular pathtogether with the chains 302.

A bracket 304 is secured to one of opposite ends of all or some of theflights 303 (that end over the flight 303 shown in FIG. 1 so far as theillustrated embodiment is concerned) and carries a roller support shaftso as to extend outwardly therefrom with a roller 305 mounted on a freeend of such roller support shaft. This roller 305 on all or some of theflights 303 can undergo a circulatory motion along a generallyrectangular path including an upper horizontal path component adjacent afluid surface level 306 of the sewage in the sewage settling poolextending in a direction shown by the arrow in FIG. 1, a diagonallydownwardly lowering path component, a lower horizontal path componentextending along the bottom of the sewage settling pool and an elevatingpath component, before it is brought to a position immediately beneaththe fluid surface level 306.

A scum removal apparatus is provided with a trough 308. This trough 308is of a generally U-shaped cross-section and includes a rear wall 308a,a major portion of which is sunken beneath the fluid surface level 306,but having an upper portions protruding above the fluid surface level306, a bottom wall 308b positioned beneath the fluid surface level 306,and a front wall 308c of a height lower than that of the rear wall 308ahaving an upper portion positioned beneath, but adjacent to the fluidsurface level 306. A front flange 308d is integrally formed with thefront wall 308c so as to protrude frontwardly from the upper portionthereof in a direction opposite to the rear wall 308a.

The trough 308 is of the generally U-shaped cross-section openingupwardly and, also, diagonally frontwardly and is of a length slightlysmaller than the width of the sewage settling pool. This trough 308 isfixedly installed in the sewage settling pool with its lengthwisedirection oriented widthwise of the sewage settling pool. Opposite endsof the trough 308 are provided with respective end plates 308e. Aconnecting trough 311 inserted through and fixed in a wall forming thesewage settling pool with its opposite ends protruding outwardly inopposite directions from the wall of the sewage settling pool is boltedto each end plate 308e by means of a flange 311a integral with theconnecting trough 311.

The connecting trough 311 is of a generally square cross-section and isused to communicate the troughs 311 in the neighboring sewage settlingpools. It is to be noted that the trough 308 is so slightly inclinedwith one end thereof held at a level higher than the opposite endthereof that fluid can flow from the higher end of the trough 308towards the lower end thereof by the effect of a gravitational force.This can in practice be accomplished by setting the bottom wall 308b ofthe trough 308 inclined. Therefore, scum and water component can begathered having flowed in one direction and then guided to the nextsucceeding treatment system.

An elongated bottom seal member 312 of a generally U-shapedcross-section made of rubber material is rigidly secured to the frontflange 308d by means of an elongated retainer plate 313. This bottomseal member 312 has rear and front wall portions, the rear portionhaving a height greater than that of the front wall portion. Bearings314 are fixedly connected to opposite respective ends of the frontflange 308d, and a tubular rotary shaft 315 is supported by thesebearing 314 so as to extend substantially parallel to the front flange308d.

A weir member (a float) 317 is supported by the rotary shaft 315 so asto undergo a rocking motion about the longitudinal axis of the rotaryshaft 315. The weir member 317 is of a generally fiat tubularconfiguration having a generally elliptical cross-section and of alength sufficient to extend widthwise of the sewage settling pool. Therotary shaft 317 has front and rear rounded sides with the rotary shaft315 extending through the rear rounded side thereof. Opposite ends ofthe weir member 317 have respective end plates 318 rigidly securedthereto with opposite ends of the rotary shaft 315 extending outwardlytherethrough to left-hand and right-hand sides.

Each of the end plates 318 is sandwiched between sealing means 320provided on the trough 308. The sealing means 320 comprises a fixedplate 321 fixed to each end of the trough 308 so as to extend uprightand having a gap between left-hand and right-hand portions thereof, fiatrubber seal plates 322 disposed on respective sides of the fixed plate321, main seals 323 each having one end formed into a tapered lip andseal retainers 324, all of which are fastened together by means of boltsand nuts. The end plates 318 can move from and aft in gaps formed amongthese elements to avoid any possible leakage of water component from thefront.

It is to be noted that the front rounded side of the weir member 317 hasa plurality of recesses 317a defined therein so that relatively largescum lumps can be drawn by these recesses 317a the first thing.

Reference numeral 325 represents a bracket secured to a side wall 310 ofthe sewage settling pool. This bracket 325 has a single operating arm327 having a generally intermediate portion rotatably connected theretoby means of a rotary support shaft 326 while extending transverse to therotary support shaft 326. The operating arm 327 has a front free endprovided with a follow-up member 328 and also has a rear free endoperatively coupled with a rod 329.

It is to be noted that, where the weir member 317 has a relatively smallwidth, an supplemental element 331 may be connected to one or each endof the weir member 317 by means of a bolt 330 threaded thereto throughthe supplemental element 331 as shown in FIG. 5. In such case, thesupplemental element 331 may have its tip provided with sharpprojections 333 effective to break the scum S into pieces.

The operation of the scum removal apparatus of the above describedconstruction is shown in FIGS. 3 and 4.

Assuming that temporary contact points in the follow-up member 328 areexpressed by a, b, c, d and e, from the front to the rear, respectively,by the time the roller 305 is brought into contact with the contactpoint a of the follow-up member 328, the weir member 317 is positionedstill above the fluid surface level 306. However, during a periodsubsequent to the contact of the roller 305 with the contact point a andprior to the contact of the roller 305 with the contact point b, thefollow-up member 328 is lifted while the weir member 317 is loweredbeneath the fluid surface level 306 by means of the operating arm 327and the rod 329. When the roller 305 relatively rolls over to thecontact point b, the weir member 317 is held substantially horizontallyto draw a relatively large amount of the scum S.

When the roller 305 rolls from the contact point b over to the nextcontact point c in the follow-up member 328, the follow-up member 328 isconversely lowered a slight distance with the weir member 317consequently lifted but still beneath the fluid surface level 306 and,in this condition, the amount of water component drawn thereby issomewhat restricted. However, some of the scum S far away from thetrough 308 are effectively drawn as described above. When the roller 305rolls over to the contact point d, the weir member 317 is lowered againto draw a relatively large amount of the scum S. When the roller 305 issubsequently brought into contact with the contact point e in thefollow-up member 328, the follow-up member 328 is lowered while the weirmember 317 is floated above the fluid surface level 306 with theconsequence that the drawing of the scum S is temporarily interrupted.During this condition, the seal is assuredly and simply achieved by thebottom seal 312, the sealing means 320, the end plates 318 and others.

It is to be noted that, as shown in FIG. 1, a shaft X may be mounted bya plurality of bearing (not shown) so as to extend parallel to thelengthwise direction of the sewage settling pool for rotation about thelongitudinal axis thereof and that an auxiliary arm 328b may beconnected to the shaft X so as to extend perpendicular thereto while afollow-up member 328a having a free end provided with a plurality ofcorrugations is fitted to a free end of the arm 328b. In such case, whenthe roller 305 approaches, the follow-up member 328a is selectivelyshifted upwardly and downwardly about the shaft X to thereby cause theweir member 317 to be elevated and lowered by a transmission mechanismwith respect to the fluid surface level 306.

FIGS. 6 to 8 illustrate the scum removal apparatus of a water-levelfollow-up type wherein the height of the weir member 317 can beautomatically adjusted in response to a change in position of the fluidsurface level 306 and which is operable to remove the scum in a mannersimilar to that described above. In this embodiment, like parts aredesignated by like reference numerals except for some of them. In thisscum removal apparatus, the operating arm 327 has a rear end fitted witha shaft 401 having an elongated hole 400 through which the rod 329 isinserted.

This shaft 401 has an arm 402 connected thereto so as to extendperpendicular thereto, said arm 402 having a front end mounted with abalancer 403 and a rear end adapted to engage a generally L-shapedstopper 404 mounted on the trough 308.

Before the roller 305 is brought into abutment with the follow-up member328, the rear end 402a of the arm 402 is engaged with the stopper 404 tokeep the arm 402 substantially horizontally and, therefore, theelongated hole 400 lies vertically. The rod 329 can move up and downthrough the elongated hole 400 and, accordingly, when the weir member317 attempts to move up and down in response to a change in fluidsurface level, the rod 329 independently moves up and down relative tothe elongated hole 400 in the arm 402 then held at a predeterminedposition, thereby accommodating the change of the fluid surface level.

After the fluid surface level has changed, and when the roller 305 isbrought into abutment with the follow-up member 328 as shown in FIG. 8,the rear end of the operating arm 327 shifts downwardly causing the arm402 to disengage from the stopper 404 and, at the same time, the shaft401 is twisted by the action of the balancer 403, resulting in that therod 329 is trapped in the elongated hole 400. As a result thereof, therod 329 is lowered from the operating arm 327 through the shaft 401 todepress the weir member 317 downwardly. When the rod 329 subsequentlyreturns to assume a vertical position after having transmitted the upand down movement, it can freely move vertically within the elongatedhole 400 to pursue the fluid surface level.

FIGS. 9 and 10 illustrates an another embodiment of the scum removalapparatus of the water-level follow-up type. This scum removal apparatusincludes an engagement plate 410 secured to an outer side of the endplate 318, said engagement plate 410 having a plurality of engagementgrooves 410a defined in an outer peripheral portion and being rotatableabout a rotary shaft 315 in synchronism with the weir member 317. Aguide plate 411 protrudes outwardly from the front wall of the trough308 and is provided with a guide portion spaced a slight distance fromand confronting the outer peripheral portion of the engagement plate410.

On the side of the operating arm 327, a rod 413 having a balancer 412 issuspended. A free end of the rod 413 adjacent the trough 308 is providedwith an engagement pin 414 positioned above the engagement plate 410 soas to protrude laterally downwardly therefrom for engagement with anyone of the engagement grooves 410a.

When the operating arm 327 is held still in a generally horizontalposition as shown in FIG. 9, the engagement pin 414 is disengaged fromand positioned above the engagement plate 410 and, therefore, both ofthe weir member 317 and the engagement plate 410 move to follow a changein fluid surface level. Even though the engagement plate 410 rotates,the engagement pin 414 can be engaged in any one of the engagementgrooves 410a since the engagement plate 410 is formed with the pluralengagement grooves 410a in its outer peripheral portion.

After the movement to follow up the change of the fluid surface level,and when the operating arm 327 subsequently operates as shown in FIG.10, the rod 413 is lowered with the engagement pin 414 brought intoengagement with any one of the engagement grooves 410a. Thereafter, theengagement plate 410 is pivoted through the rod 413. Although it mayhappen that the engagement between the engagement pin 414 and any one ofthe engagement grooves 410a may be disengaged if the angle of rotationis too great, the guide plate 411 serves to avoid this possibility. Whenthe operating arm 327 is returned to the initial position, theengagement of the engagement pin 414 with one of the engagement grooves410a is automatically disengaged as well and the operating arm 327 isheld in position to pursue the fluid surface level. It is to be notedthat the engagement grooves 410a may be formed on an outer peripheralportion of the end plate 318.

FIGS. 11 to 15 illustrate an additional example designed in associationwith the same scum removal apparatus, in which it is suggested a simplemethod of assuredly connecting a connecting trough 500, extendingthrough the side wall 310 of the sewage settling pool, with a trough515. Although the connecting trough 500 is basically a tubular member ofa generally rectangular cross-section, it has an upper wall existingonly at a generally intermediate portion thereof with its side portionscut away to provide openings 501. This is for the purpose of permittingthe trough 515 to be passed from above in the manufacturing process.

The connecting trough 500 includes a plurality of rear nuts 502positioned inwardly of the opening thereof and also provided with agenerally U-shaped seal receiving member 503 disposed on an innerperipheral portion of each axial end portion of the connecting trough500, a sealing member 504 being snugly fitted into the seal receivingmember 503. Also, L-shaped bracket 505 for receiving a channel member issecured to the outer peripheral portion of each axial end of theconnecting trough 500. A plurality of stud bolts 506 are secured to aninner surface of the bottom of the connecting trough 500, some of saidstud bolts 506 having nuts 507 threadingly mounted thereon.

This connecting trough 500 fixedly extends through a bore 508 defined inthe side wall 310 with mortar 509 filling up a gap between the outerperiphery of the connecting trough 500 and the wall defining the bore508. In installing the connecting trough 500, care must be taken thateach opening 501 of the connecting trough 500 must be positioned outsidethe side wall 310 of the sewage settling pool and that mortar 510 shouldbe filled inside the connecting trough 500 so as to conceal respectiveheads of the stud bolts 506. This is for the purpose of the liquidcomponent containing the scum can smoothly flow through the connectingtrough 500 without being disturbed by the presence of steps between thebottom wall of the trough 515 and that of the connecting trough 500. Thenuts 507 are utilized to adjust an upper surface of the mortar 510 to bein level with the bottom of any one of the neighboring inclined troughs515 when the connecting trough 500 is desired to be inclined so that theliquid component containing the scum can flow by gravity from one trough515 to the neighboring trough 515 through the connecting trough 500.

The trough 515 is of a structure having its opposite end portions of aclosed generally rectangular cross-section and its intermediate portionsopening upwardly and also partially frontwardly. The end portion of thetrough 515 is provided with perforated projecting pieces 516 securedthereto so as to protrude laterally outwardly therefrom, with theconnecting trough 500 inserted into the trough 515 through the opening501. When inserting the end portion of the trough 515 into theconnecting trough 500, a sealing member 504 is interposed between thewalls of the connecting trough 500 and the walls of the respectivetrough 515.

After the connection between each end portion of the connecting trough500 and the corresponding end portion of each trough 515, a generallyU-shaped retainer frame 517 is, as shown in FIG. 17, fixed to the endportion of the connecting trough 500 by bolts 502 with the trough 515sealingly and fixedly retained by fastening bolts 519. Thereafter, eachtrough 515 and the connecting trough 500 are fixedly fastened togetherby tension bolts 518 extending between receiving members 505 and theprojecting pieces 516.

It is to be noted that the operating arm is, as shown in FIG. 11,comprised of a first arm 511 and a second arm 512, which arms 511 and512 are connected to the rotary shaft 326 through a transverse tube 513by means of bolts 514 so that they can be adjustably shifted along anyone of X-axis and Y-axis directions perpendicular to each other. It isalso to be noted that the first arm 511 and the second arm 512 may bedisposed in respective positions reverse to those shown. This is for thepurpose of accommodating dimensional relationships with respect to thesewage settling pool. A slide tube 519 is axially slidably mounted onone end of the second arm 512 adjacent the trough 515 by means ofadjustment bolts 514, said slide tube 519 having a bottom provided witha shaft 521 which eccentrically protrude therefrom through a bracket520. The rod 522 is connected to the slide tube 519 through the shaft521. A distal end of the second arm 512 also has a slide tube 523mounted thereon through bolts 514 so that a hand-operated handle 525inserted in a tubular member 524 mounted on the slide tube 523 can beadjusted in position.

FIG. 16 illustrates another example of fixedly connecting a connectingtrough 600 in a side wall 601 of the sewage settling pool. Thisconnecting trough 600 includes a pair of fixtures 602 secured to agenerally intermediate portion of the wall forming the connecting trough600. Each of these fixtures 602 has an engagement groove 602a definedtherein so as to open in one direction. On the other hand, a bottom walldefining a bore 603 in the side wall 601 is provided with two bolts 604partially embedded in upright position so that corresponding plural nuts605 and plural washers 606 can be mounted on each of them.

After the nuts 605 and the washers 606 have been set on each of thebolts 604 so as to define respective seats, the fixtures 602 areconnected thereto with the engagement grooves 602a receiving theassociated bolts 604 while seated against the seats. Then, after theconnecting trough 600 has been mounted and set in position, theremaining nuts 605 and the remaining washers 606 are set on the bolts604 to fix the connecting trough 600. With this connecting system, sinceit is an adjustable type, the level of the connecting trough 600 can beaccomplished easily. It is to be noted that, after the connection of theconnecting trough 600 to the side wall 601, a gap formed between thewall defining the connecting trough 600 and the wall defining the bore603 is filled up by mortar to achieve a fluid tight seal.

FIG. 17 illustrates an example in which a weir member 650 having agenerally elliptical cross-section (or of a generally ovalcross-section) adapted to move up and down in a vertical direction infront of the trough 651. Stays 652 protrude from opposite end portionsof a trough 651 with rollers 653 mounted in the stays in a longitudinalrow. Generally Y-shaped sealing members 654 are secured to the frontwall of the trough 651 so as to extend widthwise of the trough 651 andare so bent and so shaped as to extend to left-hand and right-hand sidesof a weir member 650. Guide shafts 655 extend vertically from the stays652, along which the weir member 650 moves up and down in slidingrelation thereto. Upper and lower side portions of the weir member 650have bushings 656 of nylon secured thereto.

When an operating arm 657 pivots downwards by the action of a follow-upmember, the weir member 650 then floating is lowered beneath the fluidsurface level through a rod 658 whereby the scum floating on the fluidsurface level can be drawn towards the trough 651. On the other hand,when the operating arm 657 returns to the initial position, the weirmember 650 floats by the effect of its own buoyancy to halt the flow ofthe scum towards the trough 651.

FIG. 18 illustrates an additional example in which, in the scum removalapparatus comprising a trough 701 fixed between connecting troughs 700and a weir member positioned in front of the trough 701, the up and downmovement of the weir member relative to the fluid surface level iscarried out by the utilization of a driving power delivered from asediment or mud scraping device. More specifically, reference numeral702 represents rails disposed on left-hand and right-hand portions ofthe bottom of the sewage settling pool along which a carriage 703 canreciprocatingly move in a direction lengthwise perpendicular to theplane of the drawing, that is in a direction lengthwise of the sewagesettling pool. The carriage 703 includes a sediment scraping plate 704so designed and so structured as to successively scrape sediment,settling on the bottom of the sewage settling pool, towards a pit. Whilethis operation is well known as accomplished by a drive motor (notshown) and a rope 705, this example intends to utilize a driving powerdelivered therefrom for the scum removal apparatus. For this purpose,the movement of the rope 705 is taken out of the sewage settling pooland is utilized to drive the weir member to move up and down withrespect to the fluid surface level. It is, however, to be noted that thecarriage 703 is provided with a storage casing 706 which may containearthworms or biological agents for decomposing the sediment.Alternatively, arrangement may be made to blow air from any suitablesite to achieve an aeration. Also, the carriage 703 may have columns 707mounted thereon for connection with a transverse frame 708 and ropes 709or any other rod members are suspended between the carriage 703 and thetransverse frame 708 to facilitate settlement of the sewage.

FIG. 19 illustrates an additional suggestion in which a telescopicallyexpandable weir member 751, expandable in a vertical direction andhaving a generally W-shaped cross-section, is fitted to the front wallof a trough 750. This weir member 751 is of an elongated configurationextending widthwise of the trough 750 and is made of soft material suchas plastics or rubber. A fluid pressure preventive covering 752 isprovided frontwardly of the weir member 751 and is reversible upsidedown about a hinge 753 to clean the weir member 751. A reinforcementplate 754 is fitted atop the weir member 751, through which plate 754can the weir member 751 be selectively expanded and contracted byoperation of a transmission mechanism. This reinforcement plate 754 hasa plurality of recesses 755 defined at appropriate locations for receiptof large scum lumps and also has an auxiliary float 756 secured to afront portion thereof for stabilizing its operation.

FIGS. 20 to 22 illustrate a further additional example. A plurality ofsewage settling pools 800 are arranged in side-by-side relationship witheach other, one side of each sewage settling pool being communicatedwith the next sewage settling pool through respective troughs 801 thatare fluid-connected with each other through a respective connectingtrough 802 as is the case in the previously discussed embodiment, saidtroughs 801 and said connecting troughs 802 being so inclined slightlythat the water component containing the removed scum can flow from onesewage settling pool to the next adjacent sewage settling pool. As isthe case with the previously discussed embodiment, a hollow weir member803 of a generally elliptical cross-section having its bottom sidesealed by a sealing member 804 in FIG. 21 is supported by the front wallof each trough 801 for movement up and down, a pivotal movement of theweir member 805 being accomplished by causing opposite ends of a rotaryshaft 803, extending through the weir member 803, to be rotatablysupported by bearings 806 in FIG. 22.

Opposite ends of the weir member 803 in each of the sewage settling pool800 have respective sealing plates 807 secured thereto for rotationtogether with the weir member 803. The sealing plates 807 secured to theopposite ends of the weir member 803 cooperate with respective sealreceptacles (side seals) 808, one on each end of the trough 801, todefine a sealed structure. A front portion of the trough 801 opens inthe form of a generally U-shaped opening, and when the weir member 803is brought to a position beneath the fluid surface level, the watercomponent containing the scum having overflown the weir member 803 canbe drawn into the trough 801 through this opening.

In this example, if the plural weir members 803 for the sewage settlingpools 800 are driven in synchronism with each other, the water componentcontaining scum in all of these sewage settling pools can besimultaneously drawn into the respective troughs 801 and, at a distalend of the trough 801, an overflow of the water components may occur tosuch an extent as to result in an excessive supply of the watercomponent to a scum separating machine installed in the next successivetreatment site.

To alleviate this possible problem, this example has been conceived.More specifically, as shown in these figures, a single drive shaft 810connected together with the neighboring one by connecting tube isdisposed within the troughs 801 and the connecting troughs 802 and isdriven by the utilization of a driving force in the sediment scrapingdevice by training an endless chain 813 in FIG. 20 between a sprocketwheel 812, mounted on an intermediate shaft 811 used for driving thechain 813, and a sprocket wheel 812 mounted on the drive shaft 810.

Respective outer peripheral portions of the drive shaft 810 which arepositioned within the associated troughs 801 are, as shown in FIG. 21,provided with rotary plates 809, each of said rotary plates 809 having adrive pin 814 secured thereto so as to protrude outwardly therefromwhile a cam plate 815 is secured to each sealing plate 807 for receivingthe respective drive pin 814. The cam plate 815 and the sealing plate807 for each trough 801 are pivotally connected together by means of arespective pin 816 at a lower portion so that, by adjusting anadjustment bolt 817 at an upper portion, the angle between the cam plate815 and the sealing plate 807 can be adjusted.

Although the drive pin 814 associated with the illustrated trough 801 isheld at such a position as shown, the drive pin 814 associated with theneighboring trough 801 is offset a predetermined angle relative to thedrive pin 814 associated with the illustrated trough 801. In otherwords, where the number of the sewage settling pools 800 is ten, thedrive pins 814 associated with these ten sewage settling pools 800 areoffset from each other an angle of 360 degrees divided by the number ofthe sewage settling pools 800, that is, 36 degrees.

Accordingly, when the drive shaft 810 is driven by the utilization ofthe driving power delivered from the intermediate shaft 811, the derivepin 814 at one end of the sewage settling pool 800 pushes the associatedcam plate 815 forwardly to press the weir member 803 down until it comesbeneath the fluid surface level. At the time this weir member 803 ismoved a certain distance forwardly, the drive pin 814 in the neighboringtrough 801 actuates the associated cam plate 815 to actuate thecorresponding weir member 803. In this way, at intervals of apredetermined time, the weir members 803 are successively actuated. As aresult thereof, the water component containing the scum will not bedrawn into all of the troughs 801 at a time and, therefore, thepreviously discussed problem is alleviated. The weir members 803 returnto the initial position above the fluid surface level by the effect oftheir own buoyancy. Also, there is a case in which no driving power istaken from the intermediate shaft 811 and it may be so constructed as tobe driven by a dedicated motor. Furthermore, each of the drive pins 814may have a roller mounted thereon.

In the meantime, in association therewith, another additional example isalso suggested as shown in FIG. 23. In this example, the trough 801 andthe lower end of the sealing plate 807 are connected together by meansof a wire 818 so that the wire 818 can undergo a pushing action from alinear condition to a deformed condition in response to rotation of thedrive pin 814. In this way, the wire 818 rotates the sealing plate 807in a forward direction to depress the weir member 803 and, therefore,the weir member 803 can be lowered beneath the fluid surface level.

A different example is suggested in FIG. 24. In this example, the weirmembers 820 are adapted to be driven respective sets of devices. In suchcase, reference numeral 821 represents a motor, and reference numeral822 represents a reduction gear unit, output shafts of them beingprovided with worm gears within a gear box 823. From these gears, aforce is transmitted to a gear perpendicular thereto, and the rotationof this gear causes a screw shaft within an upright tube 824,perpendicular thereto, to move up and down. The up and down movement ofthe screw shaft is transmitted to an operating shaft 826 causing theweir member 820 depressed at one side. Also, a force is transmitted tothe next gear box 823 through a connecting shaft 825, and the weirmember 820 at the other side is depressed by means of the screw shaftand the operating shaft 826 of a similar construction. In this way, theweir member 820 can be uniformly depressed at the left-hand andright-hand ends and, therefore, a stabilized operating condition can beattained. This set is so constructed as to have a driving power sourcefor each sewage settling pool.

INDUSTRIAL APPLICABILITY

As hereinabove described, the scum removal apparatus according to thepresent invention is installed in the initial or final sewage settlingpoor and is useful as a handy apparatus for removing and collecting scumfloating on the fluid surface level. The present invention is sodesigned as to be applicable to all apparatuses operable to remove andcollect the scum by the utilization of the driving power delivered fromthe existing movable member in the sewage treatment pool and can bemanufactured very compact in size and at a reduced cost while satisfyingthe demands of each installability at site.

What is claimed is:
 1. A scum removal apparatus comprising:a generallyU-shaped sectioned trough fixedly installed in a sewage treatment poolwith a lower portion of the trough submerged beneath a fluid surfacelevel of the pool and with an upper portion emerging upwardly above thefluid surface level, said trough having an opening defined at one sidethereof, said trough including means for discharging scum and a watercomponent, which have been introduced into the trough through theopening; a weir member operatively connected adjacent the opening of thetrough for guiding and interrupting a flow of the scum and the watercomponent into the trough; a transmission mechanism for transmitting aforce to the weir member for causing the weir member to undergo arocking motion so that an upper side portion of the weir moves up anddown with respect to the fluid surface and including a follow-up memberincluding means for being actuated in contact with a drive unit providedin each of flights within the treatment pool; said weir member being ahollow elongated member with front and rear sides; a rotary shaftlocated in the weir member at a rear side, and means for operativelyconnecting the rotary shaft at the lower portion of the trough so thatthe weir can move in the up and down position.
 2. The scum removalapparatus according to claim 1, wherein said weir further includes meansfor drawing large scum lumps.
 3. The scum removal apparatus according toclaim 2, wherein said means is a plurality of recesses.
 4. The scumremoval apparatus according to claim 3, wherein said recesses arelocated at the front side.
 5. The scum removal apparatus according toclaim 1, wherein said weir member has a rounded rear side.
 6. A scumremoval apparatus comprising:a generally U-shaped sectioned troughfixedly installed in a sewage treatment pool, with a lower portion ofthe trough submerged beneath a fluid surface level of the pool and withan upper portion of the trough emerging upwardly above the fluid surfacelevel, said trough having an opening defined at one side thereof, saidtrough including means for discharging scum and a water component, whichhave been introduced into the trough through the opening; a weir memberoperatively connected adjacent the opening of the trough for guiding andinterrupting a flow of the scum and the water component into the trough;a transmission mechanism for transmitting a force to the weir member forcausing the weir member to undergo a rocking motion so that an upperside portion of the weir moves up and down with respect to the fluidsurface and including a follow-up member including means for beingactuated in in contact with a drive unit provided in each of flightswithin the treatment pool; one side of the trough adjacent the openingis provided with a rotary shaft extending parallel to the fluid surfacelevel and operatively connected to the weir to permit the weir member tomove up and down; said weir member being a generally elongated memberhaving an elliptical cross-section with opposite ends of the weir havingrespective end plates; and means for sealing connected to said troughwith the end plates sandwiching between them said sealing means.
 7. Thescum removed apparatus according to claim 6, wherein said shaft extendsthrough said end plates.
 8. The scum removal apparatus according toclaim 7, wherein ends of said shaft are located in bearings.